<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>CSS选择器</title>
		<!-- 导入css -->
		<link rel="stylesheet" href="css/main.css">
	</head>
	<body>
		<p>白日依山尽，</p>
		<p id="p_id">黄河入海流。</p>
		<p class="p_class">欲穷千里目，</p>
		<p class="p_class p_center">更上一层楼。</p>
	</body>
</html>